Accurate anaesthetic dosage varies from patient to patient and is critical for the patient’s safety and successful sedation. The recommended standard is for an initial dose of anaesthesia based on the patient’s weight before gradually increasing the dosage until the patient loses consciousness. This dosage is estimated based on a few indirect measures such as a patient’s heart rate, blood pressure and respiration and any dosage inaccuracies or errors will result in anaesthetic-related morbidity.
In this technology, a personalised biomarker, in the form of an EEG signature, is identified which allows for a direct and accurate measurement of the level of consciousness of the patient. This correlation between an individual’s EEG signature with their level of consciousness provides a platform for future development of consciousness monitoring systems and devices with high accuracy.
The research team has identified a ‘slow-wave saturation’ EEG signature as a personalized biomarker for the accurate assessment of the level of awareness of a patient.
With complementary brain imaging methods, electrical signals are detected from adjacent of the scalp. The activity of the slow wave oscillations in the electrical signals indicate the state of true perception loss in an individual. As a patient is anaesthetised, his EEG slow waves increases till a saturation point is reached. This saturation point is an indicator for a complete loss of consciousness in a patient and corresponds with fMRI data which showed that the brain is functionally isolated from external stimuli. This EEG signature is a personalised signature as it correlates with an individual’s grey matter volume. As such, this individual signature could provide a direct indicator of a patient’s awareness and guide the anaesthesiologist in regulating a patient’s dose accordingly.
This biomarker is useful for the development of a platform in pinpointing the optimal anaesthetic dose required for the sufficient loss of consciousness in a patient. It also allows for the monitoring of a patient’s level of consciousness during surgical and intensive care anaesthesia. Hence, this technology could be either integrated with existing patient monitoring systems or anaesthesia workstations or used for the development of a stand-alone system which monitors patient consciousness levels based on slow-wave neuronal oscillations.
Anaesthesia monitoring devices are available in several forms; integrated with a multi-parameter patient monitoring system, as a part of an anaesthesia workstation or a stand-alone unit. With the aging population, rapidly increasing number of surgeries and growing awareness amongst clinicians, the global anaesthesia monitoring devices market is projected to grow at a CAGR of 12% to reach USD 1616 million by 2020.
This technology provides a direct and accurate measurement of patient consciousness. This helps in the reduction of cases of anaesthetic over-dosage and hence patient side effects and even patient morbidity. It can also help in determining the optimal anaesthesia dosage for a patient and improve the patient experience when put under anaesthesia. For example, too low a dosage may result in the patient experiencing unintended awareness and even pain during the operation while too high a dosage causes side effects and sometimes, mortality.